Method and system for aggregation of RFID signal sources and composite to develop a unique signature

ABSTRACT

A method is presented for employing radio frequency (RF) identifier (ID) transponder tags (RFID tags) to create a unique identifier, termed an RFID signature, for use within a data processing system with respect to a person or an object. An interrogation signal is transmitted toward a person or an object with which a set of one or more RFID tags are physically associated. A first set of RFID tag identifiers are obtained from an interrogation response signal or signals returned from the set of one or more RFID tags. A mathematical operation is performed on the first set of RFID tag identifiers to generate an RFID signature value, which is employed as an identifier for the person or the object within the data processing system with respect to a transaction that is performed by the data processing system on behalf of the person or the object.

This application is a continuation of application Ser. No. 11/157,449,filed Jun. 21, 2005, now U.S. Pat. No. 7,323,992, issued on Jan. 29,2008.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improved data processing system and,in particular, to a method and apparatus for employing wirelesselectrical communication for selectively locating and/or selectivelyidentifying entities.

2. Description of Related Art

There are many ways in which identification of people and objects can beaccomplished. People have physical characteristics, such as fingerprintsor distinguishing facial characteristics, that can be used foridentification. Other types of biometric data, such as data from retinalscans, may also be used. For example, an airport might use a facialrecognition system as part of its security screening. Information forhuman identification is often augmented by artificial means, such as IDbadges or smart cards, on which identification information is placed.

Inanimate objects can also be identified by inherent physical features,but man-made objects are often identified using an assignedidentification number, such as a serial number. An identification numberis applied to a man-made object in a human-readable or amachine-readable manner, which allows the man-made object to beidentified by humans or machines, as appropriate. In many cases, though,a corporation or an organization is not interested in identifying theman-made object on which the identification number is placed but yet adifferent man-made object to which the object with the identificationnumber is attached. In this manner, an object with an identificationnumber is typically used as a label to be affixed to another object. Forexample, governmental organizations are not interested in identifyinglicense plates via license plate numbers; the automobiles to which thelicense plates are attached are the specific objects that are meant tobe identified. A license plate can be regarded as a type of label ortag, similar to a label or tag that is affixed to a package or to aproduct.

There are many scenarios in which a corporation or an organization maydesire to identify a person, an animal, or an inanimate object. In somecases, an entity is tagged for a specific identification purpose, e.g.,when a person is tagged by means of an ID badge that is valid ormeaningful only for a given corporation. Even so, significant effort maybe exerted in obtaining, managing, and protecting identificationinformation to ensure that it is not abused. In other cases, an entitymight be permanently tagged in a manner that is useful for manydifferent parties, such as bar codes on product labels, and thisidentification information is freely available and generallyrecognizable.

There are some scenarios, though, in which a corporation or anorganization may desire to have a temporary ability for identifying orlocating a person or an inanimate object, and it would not beappropriate to employ the mechanisms that are noted above or otherwell-known mechanisms. For example, in some cases, it would not becost-effective to expend significant effort beforehand to registersomeone or something in order to provide a unique identification number.In other cases, it might not be appropriate to affix an identificationlabel for a temporary purpose.

Therefore, it would be advantageous to implement methods and associateddevices that enable short-term identification and location of personsand things without significant registration procedures beforehand andwithout requirements to access proprietary databases to obtainidentifying information. It would be particularly advantageous to enableshort-term identification and location of persons and things whileemploying labels or tags that have already been affixed to objects forother purposes.

SUMMARY OF THE INVENTION

A method, system, apparatus, and computer program product is presentedfor employing radio frequency (RF) identifier (ID) transponder tags(RFID tags) to create a unique identifier, termed an RFID signature, foruse within a data processing system with respect to a person or aninanimate object, primarily for temporary purposes. When an RFIDsignature is desired for a person or an object, an interrogation signalor signals is transmitted toward a person or an object with which a setof one or more RFID tags are physically associated. A first set of oneor more RFID tag identifiers are obtained from an interrogation responsesignal or signals returned from the set of one or more RFID tags. Amathematical operation is performed on the first set of one or more RFIDtag identifiers to generate an RFID signature value, which is employedas an identifier for the person or the object within the data processingsystem with respect to a transaction that is performed by the dataprocessing system on behalf of the person or the object.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, further objectives,and advantages thereof, will be best understood by reference to thefollowing detailed description when read in conjunction with theaccompanying drawings, wherein:

FIG. 1A depicts a typical distributed data processing system in whichthe present invention may be implemented;

FIG. 1B depicts a typical computer architecture that may be used withina data processing system in which the present invention may beimplemented;

FIG. 2 depicts a block diagram that shows some elements of a dataprocessing system that may be used to capture an aggregation of RFIDidentifiers and then generate an RFID signature in accordance with anembodiment of the present invention;

FIG. 3 depicts a diagram that shows an RFID aggregation transformfunction that is employed by the present invention;

FIG. 4 depicts a flowchart that shows a process for generating an RFIDsignature with respect to a transaction for a given entity in accordancewith an embodiment of the present invention;

FIG. 5 depicts a flowchart that shows a process for employing an RFIDsignature to locate a given entity in accordance with an embodiment ofthe present invention;

FIG. 6 depicts a diagram that shows a stadium in which an embodiment ofthe present invention may be employed to identify and locate personswithin the stadium or to perform various financial transactions withrespect to persons within the stadium;

FIG. 7 depicts a diagram that shows a commercial parking garage in whichan embodiment of the present invention may be employed to identify andlocate vehicles within the parking garage or to perform variousfinancial transactions with respect to vehicles within the parkinggarage; and

FIG. 8 depicts a diagram that shows an airline luggagestorage/processing facility in which an embodiment of the presentinvention may be employed to identify and locate suitcases or othertypes of luggage within the luggage storage/processing facility or toperform other types of transactions with respect to pieces of luggagewithin the luggage storage/processing facility.

DETAILED DESCRIPTION OF THE INVENTION

In general, the devices that may comprise or relate to the presentinvention include a wide variety of data processing technology.Therefore, as background, a typical organization of hardware andsoftware components within a distributed data processing system isdescribed prior to describing the present invention in more detail.

With reference now to the figures, FIG. 1A depicts a typical network ofdata processing systems, each of which may implement a portion of thepresent invention. Distributed data processing system 100 containsnetwork 101, which is a medium that may be used to providecommunications links between various devices and computers connectedtogether within distributed data processing system 100. Network 101 mayinclude permanent connections, such as wire or fiber optic cables, ortemporary connections made through telephone or wireless communications.In the depicted example, server 102 and server 103 are connected tonetwork 101 along with storage unit 104. In addition, clients 105-107also are connected to network 101. Clients 105-107 and servers 102-103may be represented by a variety of computing devices, such asmainframes, personal computers, personal digital assistants (PDAs), etc.Distributed data processing system 100 may include additional servers,clients, routers, other devices, and peer-to-peer architectures that arenot shown.

In the depicted example, distributed data processing system 100 mayinclude the Internet with network 101 representing a worldwidecollection of networks and gateways that use various protocols tocommunicate with one another, such as Lightweight Directory AccessProtocol (LDAP), Transport Control Protocol/Internet Protocol (TCP/IP),File Transfer Protocol (FTP), Hypertext Transport Protocol (HTTP),Wireless Application Protocol (WAP), etc. Of course, distributed dataprocessing system 100 may also include a number of different types ofnetworks, such as, for example, an intranet, a local area network (LAN),or a wide area network (WAN). For example, server 102 directly supportsclient 109 and network 110, which incorporates wireless communicationlinks. Network-enabled phone 111 connects to network 110 throughwireless link 112, and PDA 113 connects to network 110 through wirelesslink 114. Phone 111 and PDA 113 can also directly transfer data betweenthemselves across wireless link 115 using an appropriate technology,such as Bluetooth™ wireless technology, to create so-called personalarea networks (PAN) or personal ad-hoc networks. In a similar manner,PDA 113 can transfer data to PDA 107 via wireless communication link116.

The present invention could be implemented on a variety of hardwareplatforms; FIG. 1A is intended as an example of a heterogeneouscomputing environment and not as an architectural limitation for thepresent invention.

With reference now to FIG. 1B, a diagram depicts a typical computerarchitecture of a data processing system, such as those shown in FIG.1A, in which the present invention may be implemented. Data processingsystem 120 contains one or more central processing units (CPUs) 122connected to internal system bus 123, which interconnects random accessmemory (RAM) 124, read-only memory 126, and input/output adapter 128,which supports various I/O devices, such as printer 130, disk units 132,or other devices not shown, such as an audio output system, etc. Systembus 123 also connects communication adapter 134 that provides access tocommunication link 136. User interface adapter 148 connects various userdevices, such as keyboard 140 and mouse 142, or other devices not shown,such as a touch screen, stylus, microphone, etc. Display adapter 144connects system bus 123 to display device 146.

Those of ordinary skill in the art will appreciate that the hardware inFIG. 1B may vary depending on the system implementation. For example,the system may have one or more processors, such as an Intel®Pentium®-based processor and a digital signal processor (DSP), and oneor more types of volatile and non-volatile memory. Other peripheraldevices may be used in addition to or in place of the hardware depictedin FIG. 1B. The depicted examples are not meant to imply architecturallimitations with respect to the present invention.

In addition to being able to be implemented on a variety of hardwareplatforms, the present invention may be implemented in a variety ofsoftware environments. A typical operating system may be used to controlprogram execution within each data processing system. For example, onedevice may run a Unix® operating system, while another device contains asimple Java® runtime environment. A representative computer platform mayinclude a browser, which is a well known software application foraccessing hypertext documents in a variety of formats, such as graphicfiles, word processing files, Extensible Markup Language (XML),Hypertext Markup Language (HTML), Handheld Device Markup Language(HDML), Wireless Markup Language (WML), and various other formats andtypes of files.

The present invention may be implemented on a variety of hardware andsoftware platforms, as described above with respect to FIG. 1A and FIG.1B. More specifically, though, the present invention is directed to acomputer system as described in more detail below with respect to theremaining figures.

As noted above, there are some scenarios in which a corporation or anorganization may desire to have a temporary ability for identifying orlocating a person or an inanimate object, yet it would not beappropriate to employ well-known mechanisms. In some cases, it might notbe appropriate to affix an identification label to someone or somethingfor a temporary purpose. In other cases, it would not be cost-effectiveto expend significant effort beforehand to register someone or somethingin order to provide a unique identification number. For example, aformal registration process can be time-consuming and, therefore,relatively expensive for the purpose that is to be achieved. Moreover,for many purposes, persons may object to a registration process as aninvasion of privacy because of the personal data that would need to begathered during a registration process.

The present invention provides a solution that enables short-termidentification of persons and/or things without significant registrationprocedures and without requirements to access proprietary databases toobtain identifying information. More advantageously, the presentinvention accomplishes the short-term identification of persons and/orthings without requiring the temporary affixation of labels or tags topersons or things specifically for the short-term identificationpurpose. In addition, the present invention provides the ability in manycases to accomplish a location operation within certain bounds during ashort-term time period in which the short-term identification purpose isactive.

The present invention accomplishes these goals by leveragingidentification information that has already been affixed or juxtaposedto persons or objects for other purposes. More specifically, the presentinvention leverages the presence of a set of ubiquitous RFID tags thathave already been affixed or juxtaposed to persons or objects; a set ofRFID tags are physically associated with, i.e. physically connected toor physically touching, a person or an object such that when the personor the object is translated, re-oriented, or otherwise moved, the set ofRFID tags are also moved with the person or the object so that the RFIDtags remain collocated with the person or the object.

The use of radio frequency (RF) identifier (ID) transponders, also knownas RFID tags, has grown in prominence as a way to compile data regardingan object to which the RFID transponder is affixed. RFID transpondershave been used in a variety of automatic data identificationapplications. An object can be tracked in terms of location of theobject, e.g., indication at a particular place at a particular time or aseries of locations over a period of time, or in terms of identificationof the object, e.g., indication of the object as distinguished fromother similar objects in proximity to the object.

RFID transponders can be manufactured with a variety of characteristicsand capabilities. A type of RFID transponder that is termed a “passiveRFID tag” can extract its power from the electromagnetic field or signalthat is provided by an interrogator device. Under a technique referredto as backscatter modulation, the RFID transponders transmit stored databy reflecting varying amounts of an electromagnetic field provided by anRFID interrogator by modulating their antenna matching impedances. Atype of RFID transponder that is termed an “active RFID tag” may includeits own power source, such as a small battery. An RFID transponder maybe accompanied by a semiconductor memory in which digital informationmay be stored or other electronic circuitry for more advanced dataprocessing characteristics.

RFID transponders can be manufactured in very small, lightweight, andinexpensive units. RFID transponders that extract their power from theinterrogating signal are particularly cost-effective since they lack apower source that would add to cost and weight. In view of theseadvantages, usage of RFID tags is expected to become ubiquitous. Forexample, the ability to place RFID tags in product labels has led tousage of the term “smart labels”, which are expected to be placed on allretail items.

RFID transponders can be used in many types of applications, such asretail transactions or applications in which it is desirable to trackinformation with respect to a moving or inaccessible object. One suchapplication is to affix RFID transponders to packages or parcels,thereby replacing the functionality of a typical bar code. An RFIDreader, i.e. an RFID interrogator device, that is located adjacent tothe conveyor belt can recover information from the RFID transponder ofeach tagged object that passes the interrogator device no matter whatthe orientation of the package on the conveyor belt. The RFIDinterrogator may then communicate the collected information to acomputer or computer network for further processing by a softwareapplication. Through these types of applications, RFID technology may beused to identify objects automatically and without manual handlingoperations as is required in most bar code systems.

While many different applications and supporting technologies for RFIDtags exist in the prior art, a common characteristic among each of theseapplications is that a reader or interrogator identifies an RFID tag. Inother words, some type of identifier is obtained from an RFID tag, whichis then communicated to a data processing system for some usefulpurpose. The present invention recognizes that pre-existing RFID tagscan be used for certain short-term identification and/or locationpurposes, as explained in more detail hereinbelow with respect to theremaining figures.

With reference now to FIG. 2, a block diagram depicts some elements of adata processing system that may be used to capture an aggregation ofRFID identifiers and then generate an RFID signature in accordance withan embodiment of the present invention. Computer system 202 is a dataprocessing system, which may represent a stand-alone computer, such asserver 102 in FIG. 1A, or a networked system, such as system 100 in FIG.1A. RFID aggregation application 204 executes within computer system 202to control RFID reader or interrogator device 206 to generate RFIDsignatures; the generation of RFID signatures is explained in moredetail further below.

RFID reader device 206 includes CPU 208 for executing software and/orfirmware, which may be stored within memory 210. Control logic 212 mayinclude signal processing functionality or other electronic circuitry.RF interface 214 provides an interface between software functionalityand hardware functionality for accepting commands to transmit/receivedsignals to/from RFID tags and for reporting information that is capturedfrom RFID tags for subsequent use by other components within the dataprocessing system. RFID interface 214 controls RF transceiver 216, whichtransmits and receives RF signals via antenna 218 to RFID tags.

FIG. 2 shows a typical person as being physically associated withmultiple RFID tags in a typical fashion. Person 220 may be assumed to bewearing various items of clothing that are not explicitly illustrated inthe figure. Several items of clothing have an associated RFID tagaffixed to them in some manner such that person 220 carries multipleRFID tags 221-225 as person 220 wears the items of clothing. Forexample, an RFID tag may be sewed or glued to a cloth label that issewed or glued to an item of clothing. As person 220 wears anRFID-tagged item of clothing, the RFID tag remains in close proximity toperson 220, thereby physically associating an RFID tag with person 220.It should be noted that the present invention may also be used withinanimate objects or things, as illustrated in other figureshereinbelow. In the example that is shown in FIG. 2, person 220 wearsitems of clothing to which are affixed RFID tags 221-225: RFID tag 221may be affixed to a shoe; RFID tag 222 may be affixed to a sock; RFIDtag 223 may be affixed to a pair of pants; RFID tag 224 may be affixedto a belt; and RFID tag 225 may be affixed to a shirt.

When person 220 is in close proximity to RFID reader device 206, RFIDreader device 206 is manually or automatically triggered to transmitinterrogation signals; the distance within which person 220 is requiredto be may vary depending on the technology that is used by RFID readerdevice 206. As RFID tags 221-225 receive an interrogation signal orsignals from RFID reader device 206, each of RFID tags 221-225 generatea response signal, and the response signals are detected by RFID readerdevice 206. Each of the response signals carries data that includes anRFID tag identifier that is encoded within the response signal in anappropriate manner. An RFID tag identifier is a data value thatidentifies an RFID tag and distinguishes it from other RFID tags to somedegree. An RFID tag identifier may be a GUID identifier (globally uniqueidentifier), an identifier within a product classification, such as aUPC identifier (Universal Product Code), a serial number of some kind,or some other type of identifier. In the example in FIG. 2, it ispossible that person 220 may be physically associated with two or moreRFID tags that respond with identical RFID tag identifiers, e.g., bywearing two socks which each have an identical RFID tag.

The set of RFID tag identifiers that are determined by RFID readerdevice 206 are collected to represent a set of aggregated RFID tagidentifiers, which are processed by RFID aggregation application 204. Asexplained in more detail hereinbelow, RFID aggregation application 204generates RFID signature 226, either under the control of a user orsystem administrator or under the control of functionality thatautomatically or programmatically performs the operation. RFID signature226 may be reported to other applications 228 for subsequent use orstored within a general purpose database or a special purpose database,such as RFID signature database 230, from which RFID signature 226 maybe retrieved at some later point in time.

With reference now to FIG. 3, a diagram illustrates an RFID aggregationtransform function that is employed by the present invention. After aset of RFID tag identifiers has been accumulated with respect to a givenperson or a given object, the set of RFID tag identifiers may berepresented by a record or data structure 302 that stores the set of oneor more RFID tag identifiers within some type of memory device. At somepoint in time, data structure 302 that contains the set of RFID tagidentifiers is retrieved by RFID aggregation transform function 304,which represents functionality within software, firmware, or hardwarefor implementing the process of generating RFID signature 306. RFIDaggregation transform function 304 accepts the set of one or more RFIDtag identifiers as a set of input parameters, and RFID aggregationtransform function 304 returns RFID signature 306 as an outputparameter, which may be stored within a physical memory or transmittedvia a physical transmission medium.

An implementation of the present invention may support RFID signaturesin a variety of data formats. Hence, RFID aggregation transform function304 may generate RFID signature 306 in a variety of manners, and RFIDaggregation transform function 304 may represent a variety ofimplementations of storable software/firmware and/or hardware logic.

In one embodiment of the present invention, RFID signature 306 may begenerated by sorting the set of one or more RFID tag identifiers andthen appending the one or more RFID tag identifiers to each other tocreate a sorted series of RFID tag identifiers. At this point, the RFIDsignature 306 may be represented by a string of binary digits or bits.The sorted series of RFID tag identifiers may be compressed in anyappropriate manner, e.g., by generating a hexadecimal digit characterstring that represents the string of bits, and hence, the value of RFIDsignature 306.

In a different embodiment of the present invention, RFID signature 306may be generated by sorting the set of one or more RFID tag identifiersand then inputting the sorted series of RFID tag identifiers into ahashing function; the outputted hash value is used as RFID signature306. Again, the hash value may be compressed in any appropriate manner,e.g., by generating a hexadecimal digit character string that representsthe hash value. Other implementations of the present invention mayemploy other mathematical or logical functions for generating an RFIDsignature either in place of or in addition to those noted above.

In a preferred embodiment, RFID aggregation transform function 304 is afunction that provides a unique one-to-one mapping of an input value orvalues to an output value. Hence, RFID signature 306 is a single datavalue that acts as an aggregate identifier to uniquely represent the setof one or more RFID tags that originated the RFID tag identifiers withindata structure 302. In other words, RFID signature 306 is a single datavalue that acts as an aggregate identifier for the originating RFID tagsas a whole. Since the set of originating RFID tags may be regarded asuniquely representing a person or an object with which they arephysically associated, RFID signature 306 may be regarded as uniquelyrepresenting the person or the object that is physically associated withthe originating RFID tags.

It should be noted, however, that not all of the RFID identifiers thatare obtained from an originating set of RFID tags are necessarilyrequired to be used within RFID aggregation transform function 304; someRFID tag identifiers may be discarded before generating RFID signature306. For example, redundant RFID identifiers might be discarded, such asdiscarding one of two identical RFID identifiers from two identical RFIDtags, e.g., which might be affixed to a pair of socks. In other cases,entire classes of RFID tags might be discarded, e.g., to address privacyconcerns. A discard policy for a set of one or more RFID tag identifiersmay be obtained with reference to a database of RFID tag identifiers forthis purpose. Alternatively, a discard policy may merely indicate a typeof RFID tags to be ignored or a class of products to be ignored, such asclothing. Using a lookup operation within a non-proprietary database,such as a database of UPC codes and their associated classification ofproducts, the class of product for a correlated RFID tag could bedetermined, after which a decision is made whether or not to include itsRFID identifier in accordance with the discard policy to generate theresulting RFID signature. By stepping through the set of RFID tagidentifiers, a discard determination is made with respect to each RFIDtag identifier, thereby filtering the entire set of RFID tagidentifiers.

With reference now to FIG. 4, a flowchart depicts a process forgenerating an RFID signature with respect to a transaction for a givenentity in accordance with an embodiment of the present invention. Theprocess commences when a data processing system receives a request toperform a transaction with respect to a given or selected entity (step402). An interrogation operation is performed on the RFID tags that arephysically associated with the selected entity using an RFID reader orinterrogator device (step 404). For example, the entity might beelectromagnetically isolated from other entities to preventcontamination of the interrogation operation in which RFID tags fromother entities respond to the interrogation signals. The set of RFID tagidentifiers that are returned by the RFID tags of the selected entityare then collected (step 406). If necessary, additional identificationor identity information about the selected entity may also be obtained(step 408), e.g., a digital photograph of the selected entity, biometricdata for a natural person, dimensional data that is obtained by scanningthe entity, or some other type of data. If the entity was paused in itsmovement for the interrogation operation, e.g., by halting a walkingperson within a security checkpoint or a building entrance or bystopping a conveyance of an inanimate object, the entity may then bereleased to continue its movement.

The obtained set of RFID tag identifiers may then be filtered ifnecessary (step 410), e.g., in a manner similar to that described abovewith respect to FIG. 3. The set of RFID tag identifiers are then inputinto an RFID aggregation transform function (step 412), and an RFIDsignature value is generated (step 414). The RFID signature may then beassociated with additional identifying data for the entity if necessary(step 416), e.g., additional identification data that was obtained atstep 408. If appropriate for the current transaction or for expectedsubsequent transactions, the original set of RFID tag identifiers mayalso be stored in association with the RFID signature and any otherappropriate identification data.

At some point, the originally requested transaction is performed usingthe RFID signature as one of possibly many input parameters (step 418),and the process is concluded. For example, a sales transaction withrespect to the entity may be performed, wherein the RFID signature isused as an identifier for the entity for uniquely associating the salestransaction with the entity. In other scenarios, the RFID signature isstored for subsequent use, or the RFID signature is provided to anothermodule or application for its use. Further examples of the usage of anRFID signature are provided hereinbelow.

With reference now to FIG. 5, a flowchart depicts a process foremploying an RFID signature to locate a given entity in accordance withan embodiment of the present invention. The process commences when adata processing system receives a request to locate an entity using anRFID signature as an identifier for the given entity (step 502). TheRFID signature may have been previously generated and previouslyassociated with the entity using an interrogation and RFID aggregationprocedure that is similar to the one that is shown in FIG. 4. The RFIDsignature value is employed as a key value to lookup the original set ofRFID tag identifiers that were used to generate the received RFIDsignature (step 504), and the original set of RFID tag identifiers aretemporarily stored for subsequent use later in the process.

The RFID subsystem/system is then directed, either automatically orunder the control of a system administrator, to send an interrogationsignal or signals from an appropriate set of RFID interrogation/readerdevices within a given area (step 506). The location operation of thepresent process may occur within one or more areas as appropriate,depending on the coverage of one or more areas by the interrogationsignals or by the placement of interrogation devices within those areas.For example, to locate a given entity within a building, it may beappropriate to activate devices within an entire building; to locate agiven entity on a given area of a building, it may be appropriate toactivate devices only on one floor or within certain sections of asubset of adjacent floors. It should be noted that the granularity ofdistance with which the current process may locate a given entity may bedependent upon many factors: the RFID technology that is employed; thesize of a given area; the potential signal interference within a givenarea; the number of RFID reader devices within a given area; thegranularity of placement of those RFID reader devices within the givenarea; and/or other possible factors.

The RFID reader devices receive interrogation response signals from theRFID tags (step 508), and the RFID tag identifiers within those responsesignals may then be filtered if necessary (step 510), e.g., as describedwith respect to FIG. 3. The RFID tag identifiers are sorted if necessaryto assist in the following search process (step 512). The sort operationmight be performed with respect to many factors: the location of an RFIDtag's interrogation response signal in relation to nearby RFID readerdevices, i.e. the detection of a strong signal by an RFID reader devicemay imply less distance from a responding RFID tag; likely groupings ofRFID tags by classification of product, e.g., certain RFID tags forclothing are more likely to be located on a single person; and/or othersort criteria.

The sorted set of RFID tag identifiers are then searched for sets orsubsets of RFID tag identifiers that match or approximate the originalset of RFID tag identifiers for the entity that was retrieved earlier inthe process (step 514). For example, the present invention assumes thata physically associated set of RFID tags, such as a set of RFID tags onitems of clothing for a single person, may not necessarily be related inany manner, e.g., by having a common manufacturer, a common retailorigin, or any other common characteristics that might be looked up withreference to a database, such as a database of UPC codes. Hence, it ispossible that a potentially large number of RFID tag identifiers arecollected during the RFID interrogation operation, yet the presentinvention is only able to rely on spatial information with respect tothe RFID reader devices and on patterns or subgroups of RFID tagidentifiers that have been discovered. Thereafter, the collected (andpossibly sorted) set of RFID tag identifiers needs to be processed byperforming pattern matching operations or by performing dimensionalanalysis on groups and subgroups of the collected set of RFID tagidentifiers.

Using this analysis, probable sets of RFID tag identifiers are thenselected (step 516). Probable approximate locations of the given entityare then reported or returned in a response to the requesting componentof the system (step 518), and the process is concluded.

The accuracy of the reported location or locations may be high in somecases. However, the reported locations may be relative to the RFIDreader devices that are assumed to have assisted in identifying thelocation of the given entity, and the relative locations may beapproximate because of the limiting factors that were mentioned above.Hence, in some scenarios, the accuracy of the reported location orlocations may be low.

Moreover, a given entity may be identified correctly and exactly usingthe present invention. However, the present invention provides supportfor fuzzy logic in its determinations. The probability of locating agiven entity may be high in some cases, but in other cases, it ispossible that the analysis may produce estimates of multiple locationsfor the given entity with low probabilities. For example, within a givenenclosed area, it is possible that there may be more than one person orobject on which a similar set of RFID tags are affixed or are physicallyassociated. Depending on the manner in which an RFID tag is generated,e.g., whether or not the RFID tag identifiers are filtered, etc.,different persons or objects might present similar sets of RFID tagidentifiers when interrogated. In addition, the interrogation responsesignals might be muffled by interference for many reasons, therebynarrowing the detected set of RFID tag identifiers from which touniquely identify each entity. Hence, it is possible that an appropriateresult of the location process is the determination of multiple possiblelocations.

With reference now to FIG. 6, a diagram depicts a stadium in which anembodiment of the present invention may be employed to identify andlocate persons within the stadium or to perform various financialtransactions with respect to persons within the stadium. Many personsare spectators to an athletic event that is being held within stadium600, which contains multiple RFID interrogation devices 602-608throughout the stadium. Each of entrances 612-618 comprises one or moreRFID interrogation stations, which act to isolate each enteringspectator so that an accurate interrogation can be made of the RFID tagsthat are located on a spectator's items of clothing. As person 620passes through interrogation station 618, an RFID interrogationoperation is performed in accordance with the present invention, e.g.,in a manner similar to that described above with respect to FIG. 2 orFIG. 4, to produce RFID signature 622 that becomes associated withperson 620.

RFID signature 622 can be used as a temporary identifier for person 620while person 620 is within stadium 600. If person 620 is desired to belocated during the event within stadium 600, RFID interrogation devices602-608 may be employed to locate person 620 in a manner similar to thatdescribed above with respect to FIG. 5. For example, a facialrecognition function within a security application may process digitalphotographs that were captured as persons passed through the RFIDinterrogation stations of the stadium. If the security applicationindicates that an individual in one of the digital photos is wanted bylaw enforcement agencies, the present invention provides thefunctionality for locating the individual within the stadium.

When person 620 initiates certain transactions, RFID signature 622 maybe used to identify person 620 with respect to those transactions. Forexample, RFID signature 622 can be used to positively identify person620, thereby enabling event personnel to allow a person to exit andre-enter the stadium. Additional RFID interrogation stations may belocated within the stadium for special purpose transactions. Forexample, when person 620 wants to reserve a spot in a special interiorevent or interior ticket line or wants to reserve a table at arestaurant in a sky box within the stadium, person 620 may be scanned byan RFID interrogation station, thereby producing RFID signature 622 thatcan be used to identify person 620. At some later point in time, person620 may reappear, and person 620 is rescanned. By matching thepreviously generated RFID signature with the currently generated RFIDsignature, the appropriate system component can indicate that it hassuccessfully verified that person 620 is the same person that originallyinitiated a reservation transaction, thereby allowing event personnel tocomplete the transaction that is associated with the reservation.

With reference now to FIG. 7, a diagram depicts a commercial parkinggarage in which an embodiment of the present invention may be employedto identify and locate vehicles within the parking garage or to performvarious financial transactions with respect to vehicles within theparking garage. Many vehicles can be parked within parking garage 700,which contains multiple RFID interrogation devices 702-706 throughoutthe parking garage. Each of parking garage entrances 712-716 comprisesone or more RFID interrogation stations, which act to isolate eachentering or exiting vehicle so that an accurate interrogation can bemade of the RFID tags that are located on parts of the vehicle. Asvehicle 720 passes through interrogation station 716, an RFIDinterrogation operation is performed in accordance with the presentinvention, e.g., in a manner similar to that described above withrespect to FIG. 2 or FIG. 4, to produce RFID signature 722 that becomesassociated with vehicle 720. It may be assumed that a filter operationignored RFID tags that are not associated with auto parts, e.g., such asRFID tags that are easily removed or RFID tags that are affixed to itemsof clothing that are worn by vehicle operators.

RFID signature 722 can be used as a temporary identifier for vehicle 720while vehicle 720 is within parking garage 700. If vehicle 720 isdesired to be located within parking garage 700, RFID interrogationdevices 702-706 may be employed to locate vehicle 720 in a mannersimilar to that described above with respect to FIG. 5.

When the operator of vehicle 720 initiates certain transactions, RFIDsignature 722 may be used to identify vehicle 720 with respect to thosetransactions, e.g., such as allowing vehicle 720 to exit and re-enterthe parking garage in accordance with a previously purchased parkingcontract or to park in certain locations with respect to a previouslypurchased parking contract.

With reference now to FIG. 8, a diagram depicts an airline luggagestorage/processing facility in which an embodiment of the presentinvention may be employed to identify and locate suitcases or othertypes of luggage within the luggage storage/processing facility or toperform other types of transactions with respect to pieces of luggagewithin the luggage storage/processing facility. Many pieces of luggagecan be stored within luggage storage/processing facility 800, whichcontains multiple RFID interrogation devices 802-806 throughout thefacility. Each of luggage facility entrances 812-816 comprises one ormore RFID interrogation stations, which act to isolate each entering orexiting piece of luggage so that an accurate interrogation can be madeof the RFID tags that are located within on or in each piece of luggage,including RFID tags that may be affixed to items of clothing within thepieces of luggage. As suitcase 820 passes through interrogation station816, an RFID interrogation operation is performed in accordance with thepresent invention, e.g., in a manner similar to that described abovewith respect to FIG. 2 or FIG. 4, to produce RFID signature 822 thatbecomes associated with suitcase 820.

Suitcase 820 may already have a temporary, airline-provided,flight-specific, luggage tag, which itself has an affixed RFID tag 824,which may be used for most temporary identification purposes forsuitcase 820. However, there are many special purposes in which the useof the present invention is advantageous. For example, RFID signature822 is used as a temporary identifier for suitcase 820 while suitcase820 is within luggage facility 800, and RFID signature 822 providessupport for location operations, particularly if luggage facility 800processes lost luggage in which each piece of luggage must beindividually moved. If suitcase 820 is desired to be located withinluggage facility 800, RFID interrogation devices 802-806 may be employedto locate suitcase 820 in a manner similar to that described above withrespect to FIG. 5.

As yet another example of an advantageous application of the presentinvention with respect to luggage, RFID signature 822 may be used todetermine whether or not someone has tampered with suitcase 820.Assuming that identical RFID aggregation transform functions andidentical RFID tag identifier filtering functions are consistentlyapplied to suitcase 820, RFID signature value 822 should be generated ateach RFID interrogation station through which suitcase 820 passes. If anRFID signature value is generated that differs from a previouslygenerated RFID signature value for the same piece of luggage, i.e.within the same flight or trip, then the RFID interrogation station canflag the piece of luggage to indicate that someone may have tamperedwith it in some manner, e.g., to remove items of clothing or to addmalicious items.

The advantages of the present invention should be apparent in view ofthe detailed description that is provided above. One or more RFID tagsare already physically associated with a person or an object. Thepresent invention leverages this scenario to aggregate RFID tagidentifiers from those physically associated RFID tags and then tocomposite those RFID tag identifiers into an RFID signature that can beused for identification purposes, particularly for short-term ortemporary identification purposes. In this manner, the RFID signaturecan be employed as an identification token, and the RFID signature maybe used in a spatially search for a person or an object based on thepreviously generated and associated signature.

It is important to note that while the present invention has beendescribed in the context of a fully functioning data processing system,those of ordinary skill in the art will appreciate that some of theprocesses associated with the present invention are capable of beingdistributed in the form of instructions in a computer readable mediumand a variety of other forms, regardless of the particular type ofsignal bearing media actually used to carry out the distribution.Examples of computer readable media include media such as EPROM, ROM,tape, floppy disc, hard disk drive, RAM, and CD-ROMs andtransmission-type media, such as digital and analog communicationslinks.

The description of the present invention has been presented for purposesof illustration but is not intended to be exhaustive or limited to thedisclosed embodiments. Many modifications and variations will beapparent to those of ordinary skill in the art. The embodiments werechosen to explain the principles of the invention and its practicalapplications and to enable others of ordinary skill in the art tounderstand the invention in order to implement various embodiments withvarious modifications as might be suited to other contemplated uses.

1. An apparatus that employs radio frequency (RF) identifier (ID)transponder tags (RFID tags) within a data processing system, theapparatus comprising: a memory including instructions, and a processor,wherein the processor executes the instructions for: transmitting aninterrogation signal or signals toward a person or an object with whicha set of one or more RFID tags are physically associated; obtaining afirst set of one or more RFID tag identifiers from an interrogationresponse signal or signals returned from the set of one or more RFIDtags; performing a mathematical operation on the first set of one ormore RFID tag identifiers to generate an RFID signature value; receivinga request to determine a physical location of the person or the object,wherein the request contains the RFID signature value; employing theRFID signature value as an identifier within the data processing systemfor the person or the object with respect to the request to determinethe physical location of the person or the object; performing aninterrogation operation in response to the request to determine thephysical location of the person or the object; computing the physicallocation of the person or the object based on information withininterrogation response signals that are received during theinterrogation operation; and returning a response to report the physicallocation of the person or the object.
 2. The apparatus of claim 1,wherein the processor further executes the instructions for:transmitting an interrogation signal or signals in response to receivingthe request; and obtaining a second set of RFID tag identifiers frominterrogation response signals returned by a plurality of RFID tags. 3.The apparatus of claim 2, wherein the processor further executes theinstructions for: analyzing the second set of RFID tag identifiers todetermine a subset of RFID tag identifiers within the second set of RFIDtag identifiers such that the subset of RFID tag identifiers matches thefirst set of RFID tag identifiers.
 4. The apparatus of claim 2, whereinthe processor further executes the instructions for: analyzing thesecond set of RFID tag identifiers to determine a subset of RFID tagidentifiers within the second set of RFID tag identifiers such that thesubset of RFID tag identifiers approximately matches the first set ofRFID tag identifiers.
 5. The apparatus of claim 2, wherein the processorfurther executes the instructions for: determining a location of theperson or the object relative to one or more RFID reader devices thatreceived the interrogation response signals containing the second set ofRFID tag identifiers.
 6. An apparatus that employs radio frequency (RF)identifier (ID) transponder tags (RFID tags) within a data processingsystem, the apparatus comprising: a memory including instructions, and aprocessor, wherein the processor executes the instructions for:transmitting an interrogation signal or signals toward a person or anobject with which a set of one or more RFID tags are physicallyassociated; obtaining a first set of one or more RFID tag identifiersfrom an interrogation response signal or signals returned from the setof one or more RFID tags; filtering the first set of one or more RFIDtag identifiers to discard one or more RFID tag identifiers from thefirst set of one or more RFID tag identifiers prior to performing amathematical operation to generate an RFID signature value; performingthe mathematical operation on the first set of one or more RFID tagidentifiers to generate the RFID signature value; and employing the RFIDsignature value as an identifier for the person or the object within thedata processing system with respect to a transaction that is performedby the data processing system on behalf of the person or the object. 7.The apparatus of claim 6, wherein the processor further executes theinstructions for: discarding RFID tag identifiers in accordance with apolicy that indicates a type of RFID tag to be ignored or a class ofproducts to be ignored.
 8. The apparatus of claim 7, wherein theprocessor further executes the instructions for: referring to a databasecontaining information about products and associated UPC (UniversalProduct Code) identifiers for evaluating the policy with respect to aparticular RFID tag identifier.
 9. A computer program product comprisinga computer-readable medium having encoded thereon computer usableprogram code for use within a data processing system for employing radiofrequency (RF) identifier (ID) transponder tags (RFID tags), thecomputer program product comprising: computer usable program code fortransmitting an interrogation signal or signals toward a person or anobject with which a set of one or more RFID tags are physicallyassociated; computer usable program code for obtaining a first set ofone or more RFID tag identifiers from an interrogation response signalor signals returned from the set of one or more RFID tags; computerusable program code for performing a mathematical operation on the firstset of one or more RFID tag identifiers to generate an RFID signaturevalue; computer usable program code for receiving a request to determinea physical location of the person or the object, wherein the requestcontains the RFID signature value; computer usable program code foremploying the RFID signature value as an identifier within the dataprocessing system for the person or the object with respect to therequest to determine the physical location of the person or the object;computer usable program code for performing an interrogation operationin response to the request to determine the physical location of theperson or the object; computer usable program code for computing thephysical location of the person or the object based on informationwithin interrogation response signals that are received during theinterrogation operation; and computer usable program code for returninga response to report the physical location of the person or the object.